Heat pump system

ABSTRACT

A hybrid heat pump system including, as a compressor for a refrigerant circuit, an engine-driven compressor and an electric-motor-driven compressor to achieve a rational structure with redundancy. The hybrid heat pump system further includes an operation control unit and a power source unit. The operation control unit is comprised of an engine control unit controlling the operation of an engine and an electric-motor control unit controlling the operation of an electric motor, which are individually provided. The power source unit converts commercial electric power into operating electric power and supplies the operating electric power to the operation control unit. The power source unit is comprised of an engine-side power source unit supplying the operating electric power to the engine control unit and an electric-motor-side power source unit supplying the operating electric power to the electric-motor control unit, which are individually provided.

TECHNICAL FIELD

The present invention relates to a heat pump system including: acompressor for a refrigerant circuit in which a refrigerant circulates,the compressor including an engine-driven compressor configured to bedriven by an engine to compress the refrigerant and anelectric-motor-driven compressor configured to be driven by an electricmotor to compress the refrigerant; an operation control unit; and apower source unit configured to convert commercial electric power intooperating electric power and supply the operating electric power to theoperation control unit.

BACKGROUND ART

There has been a compression-type heat pump system including arefrigerant circuit (heat pump circuit) in which a refrigerantcirculates and a compressor provided to the refrigerant circuit. Amongthis type of heat pump systems, an engine-driven heat pump system(hereinafter, referred to as “GHP” occasionally) and anelectric-motor-driven heat pump system (hereinafter, referred to as“EHP” occasionally) have achieved widespread use. The engine-driven heatpump system includes an engine-driven compressor configured to be drivenby an engine. Namely, the engine-driven heat pump system uses the engineas a driving source of the compressor. The electric-motor-driven heatpump system includes an electric-motor-driven compressor configured tobe driven by an electric motor. Namely, the electric-motor-driven heatpump system uses the electric motor as a driving source of thecompressor.

In addition to them, there has been proposed a so-called hybrid heatpump system including an engine-driven compressor and anelectric-motor-driven compressor, wherein both of the engine-drivencompressor and the electric-motor-driven compressor can be used as adriving source of the compressor (see, e.g., Patent Literature 1(hereinafter, referred to as PTL 1)). The hybrid heat pump systemcontrols an operation balance between the engine-driven compressor andthe electric-motor-driven compressor to optimize factors such as theenergy cost, the burden on the environment, and/or the convenience, forexample. In this regard, the hybrid heat pump system attracts attention.

CITATION LIST Patent Literature

PTL 1: Japanese Patent Application Laid-Open No. 2013-250004 A

SUMMARY OF INVENTION Technical Problem

Conventional hybrid heat pump systems involve a problem as below. Thatis, if trouble such as an electrical leakage and/or a malfunction occursin a power source unit of a hybrid heat pump system, this makes itimpossible for an operation control unit to control operation of anengine and an electric motor, thereby leading to abnormal stop of boththe engine and the electric motor. Consequently, the hybrid heat pumpsystem cannot continue an air conditioning process in its refrigerantcircuit.

In addition, the hybrid heat pump system has a structure more complexthan those of GHP and EHP, and therefore is relatively expensive. Inorder to achieve more widespread use, the hybrid heat pump system hasbeen desired to adopt a structure that is designed as rationally aspossible to reduce the cost.

In view of the actual circumstances as described above, a main object ofthe present invention is to provide a technique for a so-called hybridheat pump system including a compressor for a refrigerant circuit, thecompressor including an engine-driven compressor configured to be drivenby an engine and an electric-motor-driven compressor configured to bedriven by an electric motor. Specifically, the technique allows thehybrid heat pump system to achieve a structure which is designedrationally to enable cost reduction and which has redundancy allowingcontinuation of operation in the refrigerant circuit even if either ofthe engine and the electric motor is abnormally stopped due to troublesuch as an electrical leakage and/or a malfunction.

Solution to Problem and Advantageous Effects of Invention

A first aspect of the present invention provides a heat pump systemincluding:

a compressor for a refrigerant circuit in which a refrigerantcirculates, the compressor including an engine-driven compressorconfigured to be driven by an engine to compress the refrigerant and anelectric-motor-driven compressor configured to be driven by an electricmotor to compress the refrigerant;

an operation control unit; and

a power source unit configured to convert commercial electric power intooperating electric power and supply the operating electric power to theoperation control unit, wherein

the operation control unit includes an engine control unit configured tocontrol operation of the engine and an electric-motor control unitconfigured to control operation of the electric motor, and

the power source unit includes an engine-side power source unitconfigured to supply operating electric power to the engine control unitand an electric-motor-side power source unit configured to supplyoperating electric power to the electric-motor control unit, theengine-side power source unit and the electric-motor-side power sourceunit being arranged in parallel.

With this configuration, even in a case where trouble such as anelectrical leakage and/or a malfunction occurs in the operation controlunit or the power source unit related to one of the engine and theelectric motor, the operation control unit and the power source unitrelated to the other of the engine and the electric motor can be keptnormal. Thus, a structure with redundancy can be achieved. Specifically,with this configuration, even in a case where one of the engine and theelectric motor is abnormally stopped due to trouble such as anelectrical leakage and/or a malfunction, the other of the engine and theelectric motor can operate to allow continuation of operation in therefrigerant circuit.

In addition, the engine control unit and the engine-side power sourceunit can be configured independently of the electric-motor-sideconfiguration. Therefore, the engine control unit and the engine-sidepower source unit can be made of many components in common with agenerally-used GHP. Meanwhile, the electric-motor control unit and theelectric-motor-side power source unit can be configured independently ofthe engine-side configuration. Therefore, the electric-motor controlunit and the electric-motor-side power source unit can be made of manycomponents in common with a generally-used EHP. Thus, the first aspectof the present invention provides a rational structure, which enablescost reduction.

Thus, the first aspect of the present invention can provide a so-calledhybrid heat pump system having a rational structure with redundancy.

According to a second aspect of the present invention, commercialelectric power is distributedly supplied to the engine-side power sourceunit and the electric-motor-side power source unit through theirrespective electrical leakage breakers.

With this configuration, even in a case where the electrical leakagebreaker connected to one of the engine-side power source unit and theelectric-motor-side power source unit is actuated to interrupt thesupply of the commercial electric power to the one of the engine-sidepower source unit and the electric-motor-side power source unit, it ispossible to continuously supply the commercial electric power to theother of the engine-side power source unit and the electric-motor-sidepower source unit without affecting the other of the engine-side powersource unit and the electric-motor-side power source unit. Consequently,even in a case where one of the engine and the electric motor isabnormally stopped as a result of actuation of its correspondingelectrical leakage breaker, the compressor associated with the other ofthe engine and the electric motor can solely operate to compress therefrigerant so as to continue the operation in the refrigerant circuit.

According to a third aspect of the present invention, one of anengine-side circuit including the engine control unit and theengine-side power source unit and an electric-motor-side circuitincluding the electric-motor control unit and the electric-motor-sidepower source unit is detachably attachable to the other of theengine-side circuit and the electric-motor-side circuit.

With this configuration, the electric-motor-side circuit is detachablyattachable to the engine-side circuit, or the engine-side circuit isdetachably attachable to the electric-motor-side circuit. By attachingthe engine-side circuit and the electric-motor-side circuit to eachother, it is possible to provide an operation control unit and a powersource unit for a hybrid heat pump system made of a combination of theengine-driven heat pump system and the electric-motor-driven heat pumpsystem. Conversely, by detaching the electric-motor-side circuit fromthe operation control unit and the power source unit for the hybrid heatpump system, it is possible to provide an operation control unit and apower source unit for the engine-driven heat pump system. Also, bydetaching the engine-side circuit from the operation control unit andthe power source unit for the hybrid heat pump system, it is possible toprovide an operation control unit and a power source unit for theelectric-motor-driven heat pump system. Thus, an easy and rational modechange between the hybrid mode and the engine-driven mode or between thehybrid mode and the electric-motor-driven mode can be achieved. Also,since many common components can be used to achieve these modes, it ispossible to further reduce the cost.

According to a fourth aspect of the present invention, the engine-drivencompressor and the electric-motor-driven compressor are connected inparallel in the refrigerant circuit.

With this configuration, the engine-driven compressor and theelectric-motor-driven compressor are connected in parallel in therefrigerant circuit. Consequently, even in a case where one of theengine and the electric motor is abnormally stopped, the compressorassociated with the other of the engine and the electric motor cansolely operate to compress the refrigerant so as to continue theoperation in the refrigerant circuit.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 A view illustrating a schematic configuration of a heat pumpsystem according to an embodiment of the present invention.

DESCRIPTION OF EMBODIMENTS

The following will describe embodiments of the present invention withreference to the drawing.

The heat pump system illustrated in FIG. 1 includes a refrigerantcircuit 10 in which a refrigerant circulates. The refrigerant circuit 10is configured to enable a so-called compression type refrigeratingcycle. In the compression type refrigerating cycle, a gas-phaserefrigerant is compressed by a compressor 11, the compressed refrigerantis condensed by a condenser so that heat of condensation from therefrigerant is released to the air, a liquid-phase refrigerant resultingfrom the condensation is expanded by an expansion valve 15, and then theexpanded refrigerant is evaporated by an evaporator so that heat ofevaporation taken from the air is absorbed to the refrigerant.

The refrigerant circuit 10 is provided with an oil separator 12 and afour-way valve 13. The oil separator 12 separates the liquid-phaserefrigerant from the gas-phase refrigerant having been compressed by thecompressor 11, and supplies the separated liquid-phase refrigerant backto the compressor 11. The four-way valve 13 is configured to change thedestination of the gas-phase refrigerant having passed through the oilseparator 12. Specifically, the four-way valve 13 changes thedestination from an outdoor-unit heat exchanger 14 provided to anoutdoor unit to an interior-unit heat exchanger 16 provided to aninterior unit, or vice versa. When the four-way valve 13 is set in thestate illustrated in FIG. 1, the outdoor-unit heat exchanger 14 servesas a condenser and the interior-unit heat exchanger 16 serves as anevaporator, so that the interior-unit heat exchanger 16 can performso-called cooling operation for cooling indoor air. Meanwhile, when thefour-way valve 13 in the state illustrated in FIG. 1 is turned by 90degrees, the outdoor-unit heat exchanger 14 serves as an evaporator andthe interior-unit heat exchanger 16 serves as a condenser, so that theinterior-unit heat exchanger 16 can perform so-called heating operationfor heating indoor air.

The heat pump system of the present embodiment includes, as thecompressor 11 for the refrigerant circuit 10, an engine-drivencompressor 20 configured to be driven by an engine 21 to compress therefrigerant and an electric-motor-driven compressor 30 configured to bedriven by an electric motor 31 to compress the refrigerant.

Namely, the heat pump system of the present embodiment is a hybrid heatpump system made of a combination of an engine-driven heat pump system(GHP) employing the engine 21 as a driving source of the compressor 11and an electric-motor-driven heat pump system (EHP) employing theelectric motor 31 as a driving source of the compressor 11. There is noparticular limitation on the type, the fuel, and the like of the engine21. Examples of the engine 21 encompass a reciprocating engine and agas-turbine engine each using city gas as its fuel.

In the refrigerant circuit 10, the engine-driven compressor 20 and theelectric-motor-driven compressor 30 are connected in parallel.Specifically, a refrigerant discharge port of the engine-drivencompressor 20 and a refrigerant discharge port of theelectric-motor-driven compressor 30 are merged with each other at alocation upstream of the four-way valve 13, specifically, at a locationupstream of the oil separator 12. Meanwhile, a refrigerant inflow portof the engine-driven compressor 20 and a refrigerant inflow port of theelectric-motor-driven compressor 30 diverge from each other at alocation downstream of the four-way valve 13, specifically, at alocation downstream of a merged point of the liquid-phase refrigeranthaving been separated by the oil separator 12.

Namely, in the refrigerant circuit 10, both of the refrigerantcompressed by the engine-driven compressor 20 and the refrigerantcompressed by the electric-motor-driven compressor 30 flow through theoil separator 12 and the four-way valve 13, which are provided in commonto the engine-side and the electric-side.

The heat pump system of the present embodiment includes an operationcontrol unit A configured to perform operation control and a powersource unit B. The power source unit B converts commercial electricpower into operating electric power, and supplies the operating electricpower to the operation control unit A. More specifically, the powersource unit B converts, with use of an alternating current(AC)-to-direct current (DC) converter and/or the like,alternating-current commercial electric power supplied from a commercialpower source 42 into direct-current operating electric power, andsupplies the direct-current operating electric power to the operationcontrol unit A.

As the operation control unit A, an engine control unit 25 configured tocontrol operation of the engine 21 and an electric-motor control unit 35configured to control operation of the electric motor 31 are providedindividually. As the power source unit B, an electric power converter 23serving as an engine-side power source unit for supplying operatingelectric power to the engine control unit 25 and an electric powerconverter 33 serving as an electric-motor-side power source unit forsupplying operating electric power to the electric-motor control unit35, which are arranged in parallel, are provided.

Specifically, the engine control unit 25 and the electric powerconverter 23 are mounted on a GHP controller 22, which is an engine-sidecircuit. In addition to the engine control unit 25 and the electricpower converter 23, a main control unit 24 configured to controloperation of the refrigerant circuit 10 is mounted on the GHP controller22. The electric power converter 23 supplies operating electric power tothe engine control unit 25. The electric power converter 23 can supplyoperating electric power not only to the engine control unit 25 but alsoto other electric components. To the electric power converter 23 of theGHP controller 22, commercial electric power that has been branched at aterminal 40, which is connected to the commercial power source 42, andhas passed through an electrical leakage breaker 28 is distributedlysupplied.

Meanwhile, the electric-motor control unit 35 and the electric powerconverter 33 are mounted on an EHP controller 32, which is anelectric-motor-side circuit provided separately from the GHP controller22. The electric power converter 33 mounted on the EHP controller 32 cansupply operating electric power not only to the electric-motor controlunit 35 but also to other electric components. To the electric powerconverter 33 of the EHP controller 32, commercial electric power thathas been branched at the terminal 40, which is connected to thecommercial power source 42, and has passed through an electrical leakagebreaker 38 is distributedly supplied.

Namely, the electric power converter 23 converts, into operatingelectric power, commercial electric power distributedly supplied fromthe commercial power source 42, and supplies the operating electricpower to the engine control unit 25. Similarly, the electric powerconverter 33 converts, into operating electric power, commercialelectric power distributedly supplied from the commercial power source42, and supplies the operating electric power to the electric-motorcontrol unit 35. As described above, the electric power converter 23,which is the engine-side power source unit, and the electric powerconverter 33, which is the electric-motor-side power source unit, arearranged in parallel.

With the operating electric power from the electric power converter 23,the engine control unit 25 controls operation of the engine 21 toactuate the refrigerant circuit 10 to perform an air-conditioningprocess or the like. Similarly, with the operating electric power fromthe electric power converter 33, the electric-motor control unit 35controls operation of the electric motor 31 to actuate the refrigerantcircuit 10 to perform an air-conditioning process or the like. Thus,either with the operating electric power from the electric powerconverter 23, which is the engine-side power source unit, or theoperating electric power from the electric power converter 33, which isthe electric-motor-side power source unit, it is possible to actuate therefrigerant circuit 10 to perform an air-conditioning process or thelike.

The GHP controller 22 and the EHP controller 32 are communicable witheach other via communication units 26 and 36. With this configuration,the engine control unit 25 and the electric-motor control unit 35 cancontrol outputs of the engine 21 and the electric motor 31 in acoordinated manner so as to optimize the energy cost, the burden on theenvironment, and/or the like while performing a requestedair-conditioning process in the refrigerant circuit 10, for example.

As described above, in the heat pump system of the present embodiment,the GHP controller 22 on which the engine control unit 25 and theelectric power converter 23 are mounted and the EHP controller 32 onwhich the electric-motor control unit 35 and the electric powerconverter 33 are mounted are provided individually and arranged inparallel. With this configuration, even in a case where trouble such asan electrical leakage and/or a malfunction occurs in one of the GHPcontroller 22 and the EHP controller 32, the other of the GHP controller22 and the EHP controller 32 is kept normal. Thus, a structure withredundancy can be achieved. Specifically, with the above configuration,even in a case where one of the engine 21 and the electric motor 31 isabnormally stopped due to the trouble as described above, the other ofthe engine 32 and the electric motor 31 can operate to allowcontinuation of an air-conditioning process or the like in therefrigerant circuit 10.

In the refrigerant circuit 10, the engine-driven compressor 20 and theelectric-motor-driven compressor 30 are connected in parallel.Consequently, even in a case where one of the engine 21 and the electricmotor 31 is abnormally stopped, the compressor 11 associated with theother of the engine 21 and the electric motor 31 that is not abnormallystopped can solely operate to compress the refrigerant so as to continuethe operation in the refrigerant circuit 10.

In addition, the electrical leakage breakers 28 and 38 are arranged atlocations downstream of the terminal 40, where commercial electric poweris branched. At locations downstream of the electrical leakage breakers28 and 38, the electric power converter 23, which is the engine-sidepower source unit, and the electric power converter 33, which is theelectric-motor-side power source unit, are respectively disposed. Thus,commercial electric power from the commercial power source 42 isbranched at the terminal 40 so as to be supplied to the electric powerconverter 23 of the GHP controller 22 and to the electric powerconverter 33 of the EHP controller 32 through the electrical leakagebreakers 28 and 38, which are provided individually. Consequently, evenin a case where one of the electrical leakage breakers 28 and 38 isactuated due to trouble, the electric power converter 23 or 33 connectedto the other of the electrical leakage breakers 28 and 38 is suppliedwith commercial electric power continuously without being affected bythe trouble, so that the engine 21 or the electric motor 31 can operatecontinuously.

Here, noise filters (not illustrated) may be individually provided atlocations downstream of the electrical leakage breakers 28 and 38. Withthis configuration, commercial electric power may be supplied to theelectric power converter 23 of the GHP controller 22 and to the electricpower converter 33 of the EHP controller 32 through the noise filters,which are provided individually. Alternatively, a common noise filtermay be provided upstream of the location where commercial electric poweris branched to be supplied to the electrical leakage breakers 28 and 38.With this configuration, commercial electric power may be distributedlysupplied to the electric power converter 23 of the GHP controller 22 andto the electric power converter 33 of the EHP controller 32 through thecommon noise filter.

The GHP controller 22 and the EHP controller 32 are arranged inparallel. This configuration can prevent the structure related to theGHP controller 22 and the structure related to the EHP controller 32from influencing each other. Thus, in a case where a generally-used GHPis modified into a hybrid heat pump system by applying the heat pumpsystem of the present embodiment to the GHP, many components in commonwith the GHP can be used in the hybrid heat pump system. This enablesreduction in cost. Meanwhile, in a case where a generally-used EHP ismodified into a hybrid heat pump system by applying the heat pump systemof the present embodiment to the EHP, many components in common with theEHP can be employed in the hybrid heat pump system. This enablesreduction in cost.

In addition, the EHP controller 32, which is the electric-motor-sidecircuit including the electric-motor control unit 35 and the electricpower converter 33 serving as the electric-motor-side power source unit,is detachably attachable to the GHP controller 22, which is theengine-side circuit including the engine control unit 25 and theelectric power converter 23 serving as the engine-side power sourceunit. Namely, merely by attaching the EHP controller 32 to the GHPcontroller 22, the operation control unit A and the power source unit Bfor the hybrid heat pump system are provided. Conversely, detaching theEHP controller 32 therefrom yields an operation control unit A and apower source unit B for the engine-driven heat pump system made of theGHP controller 22 alone. Thus, an easy and rational mode change betweenthe hybrid mode and the engine-driven mode can be achieved. Also, sincemany common components can be used to achieve these modes, it ispossible to further reduce the cost.

In order to detach the EHP controller 32 from the GHP controller 22, acommunication cable of the communication unit 36 of the EHP controller32 is disconnected from the communication unit 26 of the GHP controller22, and the electrical leakage breaker 38 of the EHP controller 32 iselectrically disconnected from the terminal 40 connected to thecommercial power source 42. In addition, in order to detach the EHPcontroller 32, other elements related to the EHP controller 32, such asthe electrical leakage breaker 38, the electric motor 31, and/or theelectric-motor-driven compressor 30, may also be detached.

Other Embodiments

(1) The embodiment described above is configured such that theengine-driven compressor 20 and the electric-motor-driven compressor 30are connected in parallel in the refrigerant circuit 10. However, thepresent invention is not limited to this configuration. Alternatively,for example, an engine-driven compressor and an electric-motor-drivencompressor may be connected in series in a refrigerant circuit. Furtheralternatively, an engine-driven compressor and an electric-motor-drivencompressor may be provided as a single common compressor, and a shaftoutput from an engine and a shaft output from an electric motor may becombined together and inputted to the common compressor.

(2) The embodiment described above is configured such that the EHPcontroller 32, which is the electric-motor-side circuit, is detachablyattachable to the GHP controller 22, which is the engine-side circuit,to enable an easy and rational mode change between the hybrid mode andthe engine-driven mode. However, the present invention is not limited tothis configuration. Alternatively, for example, a GHP controller 22,which is an engine-side circuit, may be detachably attachable to an EHPcontroller 32, which is an electric-motor-side circuit, to enable aneasy and rational mode change between the hybrid mode and theelectric-motor-driven mode.

(3) The embodiment described above is configured such that, in therefrigerant circuit 10, the refrigerant discharge port of theengine-driven compressor 20 and the refrigerant discharge port of theelectric-motor-driven compressor 30 are merged at the location upstreamof the four-way valve 13 to allow both of the refrigerant compressed bythe engine-driven compressor 20 and the refrigerant compressed by theelectric-motor-driven compressor 30 to flow through the common four-wayvalve 13. However, the present invention is not limited to thisconfiguration. Alternatively, for example, four-way valves may beprovided respectively for an engine-driven compressor and anelectric-motor-driven compressor, and a refrigerant discharge port ofthe engine-driven compressor 20 and a refrigerant discharge port of theelectric-motor-driven compressor 30 may be merged with each other at alocation upstream of a condenser. Further alternatively, a refrigerantcircuit in which a refrigerant compressed by an engine-driven compressorcirculates and a refrigerant circuit in which a refrigerant compressedby an electric-motor-driven compressor circulates may be providedindividually.

INDUSTRIAL APPLICABILITY

The present invention is applicable to a so-called hybrid heat pumpsystem including, as a compressor for a refrigerant circuit, anengine-driven compressor and an electric-motor-driven compressor.

REFERENCE SIGNS LIST

-   -   10 refrigerant circuit    -   11 compressor    -   20 engine-driven compressor    -   21 engine    -   22 GHP controller (engine-side circuit)    -   23 electric power converter (engine-side power source unit)    -   25 engine control unit    -   30 electric-motor-driven compressor    -   31 electric motor    -   32 EHP controller (electric-motor-side circuit)    -   33 electric power converter (electric-motor-side power source        unit)    -   35 electric-motor control unit    -   A operation control unit    -   B power source unit

1. A heat pump system comprising: a compressor for a refrigerant circuitin which a refrigerant circulates, the compressor including anengine-driven compressor configured to be driven by an engine tocompress the refrigerant and an electric-motor-driven compressorconfigured to be driven by an electric motor to compress therefrigerant; an operation control unit; and a power source unitconfigured to convert commercial electric power into operating electricpower and supply the operating electric power to the operation controlunit, wherein: the operation control unit includes an engine controlunit configured to control operation of the engine and an electric-motorcontrol unit configured to control operation of the electric motor, andthe power source unit includes an engine-side power source unitconfigured to supply operating electric power to the engine control unitand an electric-motor-side power source unit configured to supplyoperating electric power to the electric-motor control unit, theengine-side power source unit and the electric-motor-side power sourceunit being arranged in parallel.
 2. The heat pump system according toclaim 1, wherein the commercial electric power is distributedly suppliedto the engine-side power source unit and the electric-motor-side powersource unit through their respective electrical leakage breakers.
 3. Theheat pump system according to claim 1, wherein one of an engine-sidecircuit including the engine control unit and the engine-side powersource unit and an electric-motor-side circuit including theelectric-motor control unit and the electric-motor-side power sourceunit is detachably attachable to another one of the engine-side circuitand the electric-motor-side circuit.
 4. The heat pump system accordingto claim 1, wherein the engine-driven compressor and theelectric-motor-driven compressor are connected in parallel in therefrigerant circuit.